Swiss Re gives materials a second life

The circular economy plays a central role at Swiss Re, and the company also tangibly commits to the concept in its role as an owner-builder. Swiss Re takes its first steps in this direction with the new "Lake" building at Mythenquai, gaining valuable experience along the way.

"Swiss Re's strategy is based on moving the entire business towards a target of CO2 net zero by 2050. Circularity will be a vital component in achieving this ambitious goal", says Vincent Eckert, Head of Internal Environmental Management at Swiss Re. Swiss Re is piloting the circular economy concept in suitable areas, such as its headquarters at the Mythenquai campus in Zurich. On the campus new buildings are being constructed, and existing ones are being renovated.

The project to construct the new "Lake" building at the current Mythenschloss site is providing the company with valuable experience in relation to clearing, gutting and demolishing the building, as well as lessons for the future. "When we cleared the building in 2019, we sold on any furniture that was in usable condition, such as desks, meeting room tables and filing units, to specialist furniture dealers, so that it could be reused elsewhere", says Swiss Re Project Manager André Gaignat. Once the building had been cleared, the interior was gutted by a specialist company. Everything apart from the concrete building skeleton was dismantled. In total, 241 tonnes (18%) of the 1068 tonnes removed was reused. Some 517 tonnes (38%) were separated into separate materials for recycling and 613 tonnes (44%) were reused. A significant proportion of the second-life material, such as carpets, raised floors, doors and technical equipments like emergency power systems, was either used in a project by Zurich-based Baubüro in situ or transported to Bosnia-Herzegovina and used in construction projects there.

There are numerous reasons why certain elements and materials can be reused and others not. "The main challenge is to find buyers for the reusable material who can collect it from the demolition site and put it to use at the exact time of removal," explains the Project Manager. He goes on to explain that, in his experience, although there would be a market for the material, the removal time ends up being unworkable for potential buyers. Demolition of the remaining structure of the Mythenschloss building began in September 2020. "Essentially, the material from our demolition works is being recycled at the concrete supplier's plant and then reused in so called "recycled concrete". This recycled concrete contains not only concrete debris from our construction site, but also recycled materials from other sites", says Gaignat. If a construction site has a lot of space, the concrete plant can be constructed on site. In most cases, however, this is not possible.

Swiss Re is using the Building Information Modelling (BIM) method for the "Lake" project. According to Gaignat, generating a digital twin, i.e. a digital construction model, allows better planning, execution and subsequent management of a building thanks to the structured data foundation. This approach also forms the basis for potential use of Madaster, the Swiss material register for real estate. Using the data from Madaster, Gaignat says, the building can be defined as a material warehouse. In the event of a future building renovation, it would then be possible for the materials that become available to be "placed on the market" early enough. "Most people find it difficult to think fully about the end of a product's life, the future  event which they are unlikely to actually experience self", says Vincent Eckert. He goes on to explain that all kinds of professions, from builders to architects and suppliers, need to collaborate around the circularity model. "Circularity requires much stronger integration of all systems and processes throughout the entire lifecycle of a building", he says, adding that it is necessary to pilot enabling tools like Madaster in order to consolidate cross-over experiences and expertise.

_{This article was originally published in December 2020 on circularhub.ch, German only}